1. Field of the Invention
This invention relates to cartridge fuses and in particular to a terminal adapter configuration which makes it possible to install an electric fuse in a fuse holder which is normally adapted to receive a larger size fuse.
2. Description of the Prior Art
It is frequently desirable to replace the electric fuses in a fuse box or on a panel board with electric fuses having a smaller rating. In most instances the fuses having the smaller rating have physical dimensions that are smaller than the physical dimensions of the fuses they replace. Where this is the case, the fuses having the smaller rating usually will not properly fit the fuse clips in the fuse box or on the panel board. To enable the fuses, which have the smaller physical dimensions to be installed in intimate electrical connection with the fuse clips, it is customary to provide adapters which are attached to the end terminals of the fuses having the smaller physical dimensions. The adapters, in turn, will snugly engage the fuse clips designed for the higher rating fuses and thereby intimately electrically connect those fuses with those fuse clips. The present invention provides such an adapter for electric fuses which is simple, inexpensive, strong and extremely effective.
The fuse terminal adapters shown in U.S. Pat. Nos. 2,889,533, 3,118,035, 3,246,106, 4,128,291 and 4,613,195 are fairly typical of the adapters heretofore in use. For example, U.S. Pat. No. 2,889,533 shows a clip-type fuse holder incorporating an adapter which accommodates the installation of a fuse having either ferrule or knife-blade type terminals. U.S. Pat. No. 4,128,291 shows a clip-type fuse holder incorporating an adapter accommodating the installation of a fuse having either ferrule or knife-blade type terminals. U.S. Pat. No. 3,118,035 shows an adapter for fuses having knife-blade type terminals. U.S. Pat. No. 4,613,195 shows fuse terminal adapters for adapting both ferrule and knife-blade fuses of the rejection type.
U.S. Pat. No. 3,246,106 relates to a fuse adapter which engages one ferrule of a "J" type fuse thereby allowing installation of such fuse in an "H" type fuse holder. The fuse adapter of the '106 patent includes a ferrule receiving bore defined by a plurality of axially extending radially displaceable arcuate conducting fingers. A "circlet" encircles the ferrule gripping fingers. The fingers of this adapter flex outwardly in a manner such that the fuse ferrule contacting surface will have a varying diameter from a maximum at the outward ends of the fingers to a minimum where the fingers merge into the body of the adapter. Such an arrangement may result in poor contact with the ferrule. It is not clear how the fingers of this adapter may expand to accommodate the ferrule with the solid circlet surrounding the fingers.
The present invention is directed towards an adapter for one of the ferrule type terminals of a ferrule type cartridge fuse which makes it possible to couple the one terminal of the fuse to a fuse clip which is adapted to operably engage a terminal of a larger size. The adaptor has a ferrule receiving bore which is defined by a pair of arcuate sections. One of the arcute sections is configured to uniformly circumferentially expand to accomodate the fuse ferrule in a manner whereby both arcuate contact surface are in good electrical surface contact with the fuse ferrule.